We've just set up with an HTC Vivid here in New York — one of AT&T's first LTE devices. It's got a solid feel, though it might have a little too much glossy black plastic for some; it's offset with a small metal plate on the rear that can be slid a millimeter or two to access the battery. We've got a "4G" signal in the status bar, but not "4G LTE" — that makes sense considering that LTE isn't live in New York yet.
There's also a white version of the Vivid that's coming to market (you can find it in the gallery below), and I actually prefer it by a wide margin. The gloss works much better in white than black, typically, and this phone is no exception — and it also works well with the silver offset of the battery cover.
As for software and performance, Sense is... well, its usual self, and it's in version 3.0 here (not the 3.5 seen on the Rhyme and others). Those of you familiar with the performance of the HTC Sensation will know the 1.2GHz dual-core Snapdragon well, and it seems to work about the same here. I didn't notice any particular lag, though as with all Android devices, that doesn't mean lag won't "accumulate" over time with regular use and app installs.
Keep an eye out for our full review coming soon!